Impact of the surface characteristics of rainwater tank material on biofilm development.

In order to determine the impact of rainwater construction material on the development of a biofilm, three materials were tested: concrete, clay, and PVC. The biofilm attachment was initially more effective on clay coupons, but, after a period of three days, concrete coupons produced a greater quantity of biofilm than clay and PVC, in that order. The heterotrophic plate count in the rainwater indicated that this quantity tended to first increase following a rainfall, and then decrease.

Evidence for implication of tryptophan hydroxylase in the regulation of melatonin synthesis in ovine pinealocytes in culture.

1. Tryptophan hydroxylase (TPOH) is the first enzyme in the melatonin synthesis pathway and the rate-limiting enzyme in serotonin synthesis. We established in this study an in vitro model of ovine pinealocytes to investigate the role of TPOH in melatonin production.

Genetic variability in plasma melatonin in sheep is due to pineal weight, not to variations in enzyme activities.

This study was conducted to determine the origin of the high variability in the mean nocturnal plasma melatonin concentration (MC) in sheep. Two extreme groups of 25 lambs each [low (L) and high (H)] were obtained by calculating their genetic value on the basis of the MC of their parents. The MC of lambs was significantly higher in the H group than in the L group (L: 189.

The onset of increased melatonin secretion after the onset of darkness in sheep depends on the photoperiod.

In sheep, melatonin secretion occurs rapidly after the onset of darkness, but the interval fluctuates according to different authors. The aim of this study was to determine this interval in sheep subjected to a long or a short photoperiod. Blood samples were taken at the right jugular vein every 100 s for 1 hr after the onset of darkness.

Day/night variation of tryptophan hydroxylase and serotonin N-acetyltransferase mRNA levels in the ovine pineal gland and retina.

In mammals, the photoperiodic information, received by the retina, is transmitted to the pineal gland. In both organs, melatonin is produced and functions as a neurohormone giving temporal information to the organism. A four-step enzymatic pathway, involving in particular the tryptophan hydroxylase (TPOH), the rate-limiting enzyme in serotonin synthesis, and the serotonin N-acetyltransferase (NAT) that converts serotonin to N-acetylserotonin, allows the synthesis of melatonin.

Binding of an adenosine A1 receptor agonist and adenosine A1 receptor antagonist to sheep pineal membranes.

The pineal organ of vertebrates produces melatonin and adenosine. In lower vertebrates, adenosine modulates melatonin production. We report herein that 2-chloro-cyclopentyl-[3H]-adenosine ([3H]CCPA: adenosine A1 receptor agonist) and [3H]-cyclopentyl-1,3-dipropylxanthine ([3H]DPCPX: adenosine A1 receptor antagonist), bind specifically to sheep pineal membranes.

Innervation of the sheep pineal gland by nonsympathetic nerve fibers containing NADPH-diaphorase activity.

We used the NADPH-diaphorase histochemical method as a potential marker for nitric oxide synthase (NOS)-containing nerve fibers innervating the pineal gland of the sheep. Nerve fibers containing NADPH-diaphorase activity provide dense innervation of the sheep pineal gland. The nerve fibers were located in the pineal capsule, in the connective tissue septae separating the lobull of the gland, and penetrating between the pinealocytes.

Photoreceptor cells of the pike pineal organ as cellular circadian oscillators.

In the pike pineal, the rhythm of melatonin (MEL) secretion is driven by a population of cellular circadian oscillators, synchronized by the 24 h light/dark (LD) cycle. Because the pineal photoreceptor contains both the input and output pathways of the clock, this cell is likely to be a cellular circadian system by itself. To support this idea, we have dissociated and cultured pike pineal cells as well as purified photoreceptors.

Production of melatonin by the gilthead sea bream pineal: anin vivo andin vitro study.

This study deals with the variations of plasma melatonin content and ofin vitro pineal melatonin secretion, in one year-old male sea bream. Plasma melatonin levels varied from almost undetectable levels during the day to 150-200 pg ml(-1) during the night, in animals maintained under a light/dark (12L/12D) cycle. The duration of the nocturnal surge corresponded to the duration of the night.

Melatonin secretion in rams maintained in constant darkness depends on the timing of a single 1-hour light pulse given the previous night.

Previous data have demonstrated that a single 1-hr light pulse at night affects the secretion of melatonin in the ram if it was given at the appropriate time. This paper reports the effect on melatonin secretion of a 1-hr light pulse given at two different times at night to two groups of rams kept in constant darkness the day following light application. It appears that the animals were able to remember the light pulse if it was given 12 hr but not 9 hr after the lights were turned off.

Pineal microdialysis of the melatonin in conscious sheep: methodology, application to a diurnal rhythm and effect of isoproterenol.

This paper describes the development of a new technique to measure melatonin contents in the pineal gland of moving sheep: the microdialysis. A dialysis probe was used to collect extracellular fluid in the sheep pineal gland, but also to inject directly into it different drugs such as isoproterenol at a very low concentration. The probe was implanted the day before the beginning of the experiment in order to obtain low levels of melatonin.

Presence of nitric oxide synthase in the sheep pineal gland: an experimental immunohistochemical study.

By use of immunohistochemistry, a dense network of nerve fibres immunoreactive to the neuronal form of nitric oxide synthase (NOS, subtype I) was demonstrated in the pineal gland of sheep. The NOS-immunoreactive fibres were located in the pineal capsule and the connective tissue septae of the gland, but fibres were also present intraparenchymally between the pinealocytes. NOS-immunoreactive nerve fibres were still present in the gland 1 month after bilateral removal of the superior cervical ganglia.

The chemical neuroanatomy of the mammalian pineal gland: neuropeptides.

The mammalian pineal gland contains multiple afferent peptidergic nerve fibres. Sympathetic nerve fibres, with their origin in the superior cervical ganglia, contain neuropeptide Y colocalized with norepinephrine. Other pinealopetal nerve fibres, probably originating in the pterygopalatine ganglion, contain vasoactive intestinal peptide and peptide histidine isoleucine.

Rhythmic secretion of melatonin by the superfused pike pineal organ: thermo- and photoperiod interaction.

In the pineal organ of the pike (Esox lucius, teleost), the rhythmic production of melatonin by the photoreceptor cells is governed by a population of endogenous circadian oscillators, synchronized and entrained by the light/dark (L/D) cycle. Production of melatonin is inhibited by light and highly increased in the dark. In the present study, isolated and superfused pike pineals were exposed to a 24-hour temperature cycle of high (10 degrees C) or low (4 degrees C) amplitude, either under L/D, or under constant darkness.

Density of peptide histidine-isoleucine- and vasoactive intestinal peptide-immunoreactive nerve fibers in the sheep pineal gland is not affected by superior cervical ganglionectomy.

Peptide histidine-isoleucine (PHI) is a regulatory peptide, synthesized as part of the same propeptide that includes also vasoactive intestinal peptide (VIP). The present study describes the distribution of PHI-immunoreactive nerve fibers in the sheep pineal organ and compares their location with the distribution of VIP-immunoreactive fibers in both normal and superior cervical ganglionectomized sheep in order to elucidate the origin of the PHI/VIP immunoreactive nerve fibers. Several PHI-immunoreactive nerve fibers were present in the meninges and in the pineal capsule.

Multiple circadian oscillators in the photosensitive pike pineal gland: a study using organ and cell culture.

The fish pineal organ contains typical and, in some species, modified photoreceptor cells involved in the photoperiodic control of melatonin production. In the majority of species studied, the rhythm in melatonin production is driven by an intra-pineal circadian oscillator synchronized by the light:dark cycle. In the present study, it is shown that the endogenous rhythm in melatonin release of superfused pike pineals maintained under constant darkness is expressed at temperatures of 19 degrees C, 20 degrees C, 25 degrees C, and 30 degrees C (period > 24 hr), but not at temperatures of 10 degrees C and 15 degrees C.

Detection of estrogen receptor mRNA in trout pineal and retina: estradiol-17 beta modulates melatonin production by cultured pineal photoreceptor cells.

Pineal photoreceptor cells produce the neurohormone melatonin, a major "Zeitgeber" of the organism. This compound is involved in the control of development, growth, sexual maturation, and seasonal reproductive cycles. The present study reports that the photosensitive pineal organ and the retina of the trout express a 3.

Absence of circadian rhythm in the disposition of melatonin in the cow.

Five adult pasture-bred Prim Holstein cows were used to document the time invariance of melatonin disposition in the cow. Melatonin was administered by an intravenous route as a bolus (5 micrograms/kg of body weight) at either 1430 or 2230. Data were analysed according to a three-compartment open model with melatonin elimination from the central compartment.

[Photoreceptor cells of the pineal body in culture: effect of 17 beta-estradiol on the production of melatonin].

Pineal photoreceptor cells produce the neurohormone, melatonin, a major "Zeitgeber" of the organism. This compound has been involved in the control of development, growth, sexual maturation, and seasonal reproductive cycles. We investigated, here, the effects of estradiol-17 beta on melatonin production by cultured pineal photoreceptor cells.

Effects of light on melatonin and two enzymes leading to its production in albino (s(al-c)) and nonalbino chickens.

A gene for sex-linked imperfect albinism in the chicken (s(al)) has been associated with increased egg production with an implication that environmental light may play a role. In this study, levels of melatonin and hydroxyindole O-methyltransferase (HIOMT) and N-acetyltransferase (NAT), two enzymes leading to melatonin production, were studied in young albino and nonalbino chickens in relation to the daily light cycle, and after 19 days of constant light or dark. Differences between genotypes were found in the levels of HIOMT activity in the pineals and retinas of birds kept in constant light for 19 days.

Pineal photoreceptor cells in culture: fine structure, and light/ dark control of cyclic nucleotide levels and melatonin secretion.

Trout pineal photoreceptor cells were dissociated by trypsin-DNase digestion and further purified by a Percoll gradient centrifugation. Total cells or purified photoreceptor cells were then embedded in a collagen gel, or layered on culture-treated polycarbonate membranes, or maintained in suspension, with RPMI 1640 medium or BGjb medium. It has been shown that cells maintain a rhythmic production of melatonin for at least seven 24 h light/dark cycles under these conditions.

Pineal photoreceptor cells: photoperiodic control of melatonin production after cell dissociation and culture.

Trout pineal cells were dissociated using a trypsin-DNase digestion technique. An enriched population of photoreceptor cells was selected from a Percoll gradient centrifugation. The ability of cultured photoreceptor cells (selected or not on a Percoll gradient) to produce melatonin rhythmically was investigated during seven 24 h light/dark cycles.

Neuropeptide Y (NPY) and C-flanking peptide of NPY in the pineal gland of normal and ganglionectomized sheep.

The present immunohistochemical study describes the presence and distribution of nerve fibers containing neuropeptide Y (NPY), and C-Flanking Peptide Of NPY (CPON) in the pineal gland of the sheep. Nerve fibers were detected by using a series of antisera directed against NPY or against CPON. Many positive immunoreactive nerve fibers were identified in the pial capsule of the pineal, in connective septae and in the parenchyma between pinealocytes.